The suspect pulled a handgun and shot one round at Tonn -- and several more at a second officer who responded to the fight, the sheriff's department said.

Tonn was struck; the second officer was not hit.

The second officer -- his or her identity hasn't been released -- gave chase over the railroad tracks, and later fired at the suspect, witnesses said.

A third officer arrived to the scene a few minutes later, as well.

The gunman died from the self-inflicted gunshot wound, Uptegrove confirmed.

Tonn was pronounced dead at Kaiser South. He spent 3 1/2 years with Galt police. He was hired in 2009 from the Sacramento Sheriff's Academy.

When Tonn came to Galt, he was first assigned to patrol, before being transitioned to a member of the K-9 program.

"He really had a passion for being a canine officer," said Detective Jarrett Tonn, Kevin's cousin. "He always wanted to do it his whole life, and was really excited when he got selected to do it."

He typically served with a police dog named Yaro.

"(Tonn) was a lot of fun to work with," Uptegrove said.

The 35-year-old worked as a medic and a firefighter in New York before coming to California, the lieutenant added.

Tonn was an "extremely proactive" officer, Uptegrove said.

Everyone in town knew him, and he knew everyone, police told the media.

Tonn was also described as having "a wealth of information" and being very friendly.

A trust fund has been set up in his name at an Elk Grove bank, Premiere West. It's located at 9340 E. Stockton Blvd.; account number 82804382.

Uptegrove said at the news conference that Tonn was 31. Sgt. Jason Ramos, of the sheriff's department, later issued the correction that Tonn was indeed 35 years old at the time of his death.

The Galt Police Department said this marks the first deadly on-duty officer shooting since the department was formed in 1946. Uptegrove clarified in the news conference, once an officer died on the job previously -- but it was due to a heart attack.

The shooting comes less than two months after an animal control officer was shot and killed after being called to retrieve pets believed to have been left behind at a Galt home.

In that incident, authorities say 45-year-old Roy Marcum died when a man inside the home who had been served an eviction notice opened fire with a shotgun.